1 reply to this topic

[Shooter63]

Something strange today, I've had an MG metro head knocking about with the idea of fitting it to the Mrs Mini, I had measured the thickness before, it's had 20 thou taken off which was going to be a problem as when I built the engine I decked the block so the pistons were 10 thou down at tdc to keep the squish up. The head on the engine has 23cc chambers to keep the compression under control, (stay with me I'm getting to the point) I got the burette out today to check the chamber volume on the MG head to see how much grinding has to be done and bugger me, the head measures 22.4cc, pretty much on the Mark after I've smoothed the floor etc. Now I knew the later heads had bigger chambers, but didn't realise the bigger chambers were being cast in the MG metro era, you live and learn, but does make me wonder if the MG ever had 10-1 compression as advertised

Shooter

[Turbo Phil]

All big bore castings had a nominal chamber volume of 21.4cc from the factory, though they can vary a little.
Used heads can have quite a bit more volume simply due to valve seat recession.

Phil.